During completion of a well, the well is filled with liquid, e.g. brine, in the annulus between the intermediate casing and the production casing, which must be unloaded before production can begin. For this purpose, a pump at a top of the well pressurises the annulus with gas from the top to displace the liquid in the annulus through gas lift valves.
Known conventional gas lift valves (GLV) are designed in such a way that the GLV nearest the top opens at one pressure and the next at another pressure. The first GLV then closes at a registered pressure drop. Each GLV is thus designed to be self-operating and is designed from the dimensions of the intermediate casing, the production casing and the pressure available at the top. If the GLVs are not designed correctly, the liquid un-loading procedure fails, e.g. if one GLV does not open or another does not close in a certain order. The GLVs are often designed to close dependent on a pressure drop, which may fail if the GLV does not detect the pressure drop. The failing GLV can then be replaced from within the production casing by intervening the well with a kick-over tool, but the valve needs to be set in either an open or a closed position, depending on the situation, in order for the unloading procedure to be re-established. If the GLV is not in the right position, the unloading procedure cannot be initiated.